In general, a washing machine refers to a mechanical apparatus that cleans and quickly washes contaminants from dirty laundry such as clothes or bedclothes using a detergent emulsion and frictional action of washing water that flows from rotational motion and/or impact action with the laundry, and the like.
In accordance with a washing manner, the washing machine may be classified into (i) a pulsator type (e.g., a rotating laundry plate type) washing machine that uses a water current formed by rotating a rotating wing or pulsator at a bottom of the tub, (ii) an agitator type (e.g., rod washing type) washing machine that washes the laundry by rotating a washing rod or cylinder having a rotating wing at a center of a tub, and (iii) a drum type (e.g., cylinder type) washing machine that washes the laundry using a force that occurs when the laundry falls in the drum by rotating the drum.
In recent years, a washing machine including a bubble generating apparatus that provides bubbles and/or foam to the washing tub has been proposed to enhance washing efficiency. When bubbles generated in the bubble generating apparatus are introduced to the washing tub, since the bubbles burst due to contact with the laundry, thereby impacting the laundry, contaminants attached or adhered to the laundry may be effectively removed.
Since conventional bubble generating apparatus and conventional controllers for controlling the bubble generating apparatus are expensive, the cost of washing machine production increases.
In addition, when the bubble discharging pressure of the bubble generating apparatus is weak due to an insufficient amount of bubbles supplied to the washing tub, the washing effect of the laundry by the bubbles may be reduced.
A conventional washing machine may be disclosed in Korean Utility Model Application Publication No. 1999-0028246, published on Jul. 15, 1999.